Recently, miniaturization of the wiring structure of electronic circuits has been in accordance with demand such as reduction in size of electronic apparatuses, enhancement in performance, reduction in pricing, and so forth.
A reliability test is performed on a developed wiring structure for confirming whether or not this has sufficient reliability. Examples of such a reliability test include a HAST (Highly Accelerated temperature and humidity Stress Test) test. The HAST test is a test for evaluating insulating resistance between wirings by applying voltage between the wirings under high temperature and high humidity.
The following is reference documents:    [Document 1] Japanese Laid-open Patent Publication No. 2007-220934    [Document 2] Japanese Laid-open Patent Publication No. 64-64237